Cytochrome P-450 in hyperplastic liver nodules during hepatocarcinogenesis with N-2-fluorenylacetamide in rats.

Amount of cytochrome P-450 in the hyperplastic liver nodules was measured during hepatocarcinogenesis with N-2-fluorenylacetamide in the rat. Amount of cytochrome P-450 in the liver microsome decreased in early stage of hepatocarcinogenesis. Concentration of cytochrome P-450 in the hyperplastic nodules and their surrounding tissues was examined, using homogenate from each of them. Its amount was significantly less in the hyperplastic nodules in the 13th week than in their surrounding tissues, and became more in hyperplastic nodules in the 19th week. The hyperplastic nodules of the animals treated with phenobarbital showed almost the same amount of cytochrome P-450 as that in the controls. Amount of cytochrome P-450 in hepatoma tissues also showed similar values as that in hyperplastic nodules.